It should be noted that the oracle to be used by an attacker indicates that encrypted control is provided as a cloud service.
Most studies conducted on encrypted control consider cloud-based control systems [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, and in such cases, an attacker can freely use an encrypted control algorithm.
Therefore, the use of the oracle in the IND-PEA game is reasonable when considering the security for the encrypted control.
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